Japanese laid-open utility model 4-36788 discloses a conventional electrical connection box of this type. A locking member is pivotally mounted on a connector housing disposed on the electrical connection box. A plate spring engagement section is located on the locking member. A plate spring is elastically disposed between the plate spring engagement section and the connector housing. In this electrical connection box, once the connector is inserted and fitted in the connector housing, the locking member is pivoted to the engagement position, working against the action of the plate spring. This engages and locks the connector.
However, in the conventional electrical connection box described above, dedicated equipment is needed to elastically dispose the plate spring in the electrical connection box and to mount the locking member. This increases production costs. Furthermore, since a plate spring is required, this also increases parts costs.